This proposal outlines a tightly controlled efficacy trial designed to elucidate the potential therapeutic benefit of a walking intervention (WI), cognitive remediation therapy (CRT), as well as combined WI and CRT program towards specific aspects of gait and cognition in individuals with mild cognitive impairment (MCI). These studies are important clinically because they provide the framework for the implementation of a therapeutic program in the future which reduces falls and prevents/delays the development of dementia in the elderly. The design of the studies in this proposal significantly advance the field by providin much needed clarity to a research area that contains conflicting data on the reliability, reproducibility, robustness, and sustainability of the therapeutic benefit conferred by WI and CRT. To our knowledge this is the first study to examine the individual, and combined, effects of WI and CRT (particularly in the context of MCI). Our experimental design will contribute to the process of elucidating the mechanism(s) responsible for promoting the beneficial effects of WI and/or CRT, and contribute to designing the most effective therapeutic program in the future. Scientifically these studies are important because there is increasing interest in understanding the potential interactions between gait changes and cognitive decline during the development of dementia, and these studies are designed to examine the effects of each intervention towards cognition as well as multiple aspects of gait, under both laboratory and free-living conditions. The focus of this proposal is to test the hypothesis that implementation of a WI, CRT, or a combined WI/CRT program, will have significant and beneficial effects towards cognition and gait in elderly individuals with MCI. Additionally, we will test the related hypothesis that the combined WI/CRT program will provide synergistic benefit compared to the delivery of either WI or CRT alone. In Specific Aim 1 we will determine the effects of each intervention towards multiple gait parameters under both laboratory and free living conditions. In Specific Aim 2 we will determine the effects of each intervention towards multiple aspects of cognition. The current proposal brings to bear many of the latest technological advances, diverse clinical expertise, a powerful clinical registry, and strong clinical resources in order to understand the effects of a W, CRT, and a combined WI/CRT program using a randomized clinical trial approach. These efforts are a necessary first step for the eventual development of a therapeutic program that reduces falls/dementia in the elderly, and will significantly contribute to the understanding of th shared and selective effects of aging towards gait and cognitive decline.